When I see a sad movie, I cry. When a piece of dust gets in my eye, I shed tears. Our eyes can turn into a water fountain pretty easily. Even when we're not crying, tears are constantly being produced. Every time we blink, we spread tears over our eyes. This type of tears produced slowly and steadily. They keep our eyes smooth, clear, and free of bits of dust and pollen. Tears also keep our eyes healthy. They contain salt and proteins that nourish the eye, and the chemical called lysozyme (lie-suh-zyme) that fights germs.

If an eye gets irritated, the tear glands produce a flood of tears. This can happen when wind, smoke, or fumes strike our eyeballs. People also cry when they are sad, happy, or in pain. Tears produced by strong emotions contain hormones produced in the body. Crying washes away these hormones—and sometimes makes you feel better.

How Do Lacrimal Gland Work?

Tear Gland

On the outside edge of each eye is the lacrimal (lack-re-mal), or tear gland. It is about the size of an almond. This gland produces tears that constantly coat the eye. The tears flow through tiny ducts, or openings, onto the eyeball.

Eyelid

Every time the eyes blink, the lids push tears down toward the nose and into the lacrimal sac.

Eyeball

Tears flow across the eyeball, coating it like a film.

Lacrimal Sac

Tears drain out of the inner side of eyes through small holes. They travel down into the lacrimal sac, which is located between the eye and the top of the nose.

Nose

Tears drain from the lacrimal sac into the nose. When a person cries a lot, tears flow into the nose, so it seems like the person's nose is running.

Do Animals Have Emotions?

Humans aren't the only animals to shed tears. Most mammals have tear glands that work like ours to clean and keep eyes moist. But no one knows for sure if animals tear up from emotion. In fact, no one knows for sure if animals feel emotions. But more and more researchers are coming to believe they do.

Many scientists agree that animals feel pain, which is an emotion. But some animal experts believe they feel other emotions, as well. An experiment showed that rats feel bad when they see other rats suffering. Gorillas seem to act sad when their child dies. Mother elephants appear upset when separated from their offspring. There are many stories of a dog acting unhappy when its human owner dies. One researcher claims that birds feel many emotions and another scientist says that even fish feel fear. However, many scientists say there is no proof animals have emotions.